The Debt Investment Calculator allows you to determine when a debt will be paid off.

Principal
Balance
Owed

Annual
Interest
Rate

Current
Monthly
Payment

Additional
Monthly
Payment

Interest
Savings

Annual
Return on
Investment

Enter the current payment terms for any one of your outstanding debts, then enter an amount you could comfortably add to the payment. 
Finally, click on "Compute" to see what the return on 
your investment will be.